Method for monitoring conveyor belt splices

[0001] Conveyor belts are widely used to move minerals, coal and a variety of manufactured products from one point to another. Heavy duty conveyor belts used in mining operations can extend over distances of several miles and represent a very expensive component of an industrial material handling operation. Unfortunately, such conveyor belts are susceptible to damage from the material transported on them and a tear, cut, cut or break may appear within the tape. For example, sharp edges of the material being conveyed can have a grooving effect on the belt surface and this can lead to tearing. The segments of the conveyor belt are connected together during installation to form a continuous loop of the conveyor belt.

[0002] In order to minimize the effects of potential longitudinal tears or crossings due to high line damage, mines may use sensors to monitor such states and alert mines about an existing or potential catastrophic event. Conveyor belts that tear longitudinally often use tear detection systems to resist tearing damage to minimize downtime. Furthermore, damaged steel cables within the conveyor belt or connection defects can be monitored and repaired proactively to avoid a catastrophic event. The costs of repairing the tape to work under heavy loads and cleaning up the material spilled as a result of damage can be considerable. In the event that such damage is not immediately detected and repaired, the damage may spread as a longitudinal tear along the length of the belt or across the width of the belt as a transverse interruption, wherein the further use of the conveyor system results in additional damage to the conveyor belt and a larger downtime event for the end user. Accordingly, it is desirable to detect damage to the tape and repair the damaged area of ​​the tape before the catastrophic failure occurs. Thanks to such measures, the range of belt damages can be minimized, repairs can be simplified and spillage of the material can be reduced or avoided and the service life of the conveyor belt can be extended. wherein the further use of the conveyor system results in additional damage to the conveyor belt and a larger downtime event for the end user. Accordingly, it is desirable to detect damage to the tape and repair the damaged area of ​​the tape before the catastrophic failure occurs. Thanks to such measures, the range of belt damages can be minimized, repairs can be simplified and spillage of the material can be reduced or avoided and the service life of the conveyor belt can be extended. wherein the further use of the conveyor system results in additional damage to the conveyor belt and a larger downtime event for the end user. Accordingly, it is desirable to detect damage to the tape and repair the damaged area of ​​the tape before the catastrophic failure occurs. Thanks to such measures, the range of belt damages can be minimized, repairs can be simplified and spillage of the material can be reduced or avoided and the service life of the conveyor belt can be extended.

[0003] Over the years, a large number of belt failure detection systems have been developed and for automatic retention of further belt movement after failure. It is well known to use within antenna conveyor belts as part of a tear detection system. In a typical system, sensors in the form of conductive wire circuits are mounted or embedded in the tape and provide a tear detection tool as part of the entire tear detection system. Detection of tears is achieved by inferential detection of the "open circuit" state in one or more sensing circuits in the tape. Typically with

- the sensor circuit in the tape is inductively or capacitively coupled to an external electrical energy source relative to the belt. An open circuit in the conductive wire of the sensor can be detected by a remote receiver / transmitter (exciter / detector). It may be possible to arrange a plurality of such sensors at intervals along the conveyor, with each sensor passing within the reading range of one or more exciters / detectors at different locations. The tear will encounter and damage the proximal sensor circuit and the existence of an interrupt will be detected when the damage to the proximal sensor circuit is detected as an open circuit by the reader in the next pass. In this way, the existence of a tear will be immediately detected and repaired while minimizing further damage to the tape.

[0004] US 3 742 477 discloses an "octal" sensing circuit useful within a belt sensor system. U.S. Patent No. 3,922,661 discloses an electronic control system for conveyor belts that monitors the status of built-in sensor conductors in the belt and provides a warning indication and / or disables the conveyor when the belt or control circuit is damaged.

[0005] US patent 4 621 727 discloses a reinforced conveyor belt having a conductor for use in a tear monitoring system comprising a tape comprising: (a) an elastomeric body having an upper transfer surface and a parallel lower surface coupled to the pulley, wherein each surface extends indefinitely in the direction of belt travel; (b) a plurality of reinforcing layers disposed within the elastomer body (c) a plurality of envelopes with a low coefficient of friction material disposed within the elastomer body and disposed in a tape travel direction, each envelope forming a hollow region within the elastomer body within said envelope and (d ) a shaped guide placed within the envelope,

[0006] US 4 854 446 discloses "octal" sensor circuits spaced along the conveyor belt. More specifically, this reference discloses an endless conveyor belt having a certain feed direction, comprising: (a) an elastomeric body having a load bearing surface and a parallel surface coupled to the pulley; (b) a reinforcement layer located within the elastomer body and (c) a conductor positioned within the belt in a predetermined pattern forming a closed current path, the conductor comprising a plurality of reinforcing fibers or bands from the first metal wrapped around the conductive core of the other metal, the reinforcement fibers or bands have greater fatigue strength than the conductive core to increase the fatigue strength of the conductive core.

[0007] The patent US 6 352 149 discloses a system in which an antenna for incorporation into an electromagnetic circuit consisting of two detection heads and an electronic unit is incorporated into the conveyor belt. The coupling occurs only when the antenna passes across the detection heads and can only occur when it has not been

- 3 violated circuit integrity. More specifically, US Patent 6,352,149 discloses a conveyor belt including a tear detection sensor comprising a conductor formed into an endless loop disposed in a signal reversing configuration, the conductor intersecting itself in at least one intersection, characterized by: a conductor formed as a microlight spring wire; the conductor intersects with each other by cutting with each other so that the microlound spring wire remains substantially in a single plane throughout the sensor, taking into account the points of intersection; and a means for preventing short circuits at the intersections.

[0008] US 6,715,602 discloses a conveyor belt including a tear detection sensor comprising a conductor formed into an endless loop, characterized in that: the belt comprises at least one transponder attached to the belt in a conjugated relation with the conductor; and the transponder transmits information identifying the location of the guide along the tape.

Patent US 6 988 610 discloses an inspection system for detecting and reporting conveyor belt states, a system comprising: a controller including a connection detection program for receiving image data from at least one camera constructed and implemented for capturing an image of a conveyor belt part, for detecting a connection in the image of a portion of the conveyor belt by processing the received image data and to generate status information associated with a portion of the conveyor belt based on the detected connection.

[0010] International patent application No. WO 2007/026135 A1 discloses a system for monitoring the operation of a conveyor belt installation that comprises a conveyor belt having steel or other or magnetically permeable reinforcement material, the system comprising a field generator positioned near the conveyor belt for generating a magnetic field. a sensor unit located near the conveyor belt in a position downstream of the field generator as viewed in the normal belt travel direction, the sensing unit detecting the magnetic field emitted from the passing conveyor belt and the monitoring means for receiving data related to magnetic field properties detected by the sensor unit during pass each of the length of the conveyor belt at the sensor unit,wherein the monitoring means comprises a comparison means for comparing a further received data set to a previously received data set and an output means for providing an output signal representing damage or deterioration of the gain when the subsequent received data deviates from the previously received data in a greater than designated range.

[0011] US 7 740 130 and US 7 942 258 disclose a digital processor for use in a conveyor belt tear detector that provides excitation signals at a selected frequency to inverted and non-inverted sensor circuits on a conveyor belt and then detects corresponding received signals from sensing circuits . The digital processor then performs a fast Fourier transform on

- 4 respective received signals to provide respective frequency spectrums of the received signal. Then, the values ​​of the module and the phase of the selected frequency in the respective spectra of the frequency of the received signal are used to determine the quantitative state of the sensing circuits. The selected frequency has the smallest detectable level of ambient noise, and the value of the module is the normalized value of the module. More specifically, these patents disclose an apparatus for use in a conveyor belt tear detector that couples excitation signals to sensing circuits conveyed by a conveyor belt and then detects corresponding signals received from respective sensing circuits, the apparatus includes: an excitation frequency generator that generates excitation signals at the first frequency,

[0012] The patent US 7 810 634 and the patent US 8 256 607 disclose a monitoring system provided for a moving conveyor belt having a plurality of embedded reinforcing lines and identification marks. The tag reader detects and identifies the tag marks passing through the tag reader, while the tape monitor scans the links for detecting multiple magnetic reference points and the failure event of at least one link. The control unit communicates with the tape monitor and tag reader to monitor the tape monitor to identify multiple magnetic reference points and fault events. The control unit also obtains the location of the tape on the moving conveyor belt from the tape map based on the detected and identified identification tag and a certain magnetic reference point among a plurality of magnetic reference points. When identifying the failure event, the control unit determines the location of the fault event based on the acquired tape location.

[0013] The patent US 7 894 934 discloses a remote monitoring system of a conveyor belt for monitoring the operation of a conveyor belt in a first geographical location. The local operator panel is able to acquire and store data representing states of the conveyor belt and operating characteristics. The first and second computers in different geographical locations acquire data via the Internet. Thus, data related to the conveyor belt operating conditions can be remotely consolidated and monitored using computers in various global locations. More specifically, the patent discloses a method for remotely monitoring a plurality of states of a plurality of conveyor belts using a network-based prediction and diagnostics system that enables automatic consistent collection and consolidation of data related to the condition of the conveyor belt,

- comprising: detecting states relating to the first operational conveyor belt in the first geographic location; generating the first data in the first location in response to detected states; storing the first data in the first database in the first geographical location; acquiring first data using a monitoring computer at a monitoring location geographically distant from the first geographical location; storing the first data in the monitoring database at the monitoring location; detecting states associated with a second working conveyor belt at a second geographic location; generating second data in the second location in response to detected states; storing second data in a second database in a second geographic location; acquiring second data using a monitoring computer at a monitoring location geographically distant from the first and second geographic location; storing second data in the monitoring database at the monitoring location.

[0014] The patent US 8 069 975 discloses a system for detecting the tears of a conveyor belt with belts having tear detection inserts that can be more easily integrated with conveyor belts at a low cost. Such tear detection inserts do not adversely affect the durability of the conveyor belt and can be easily replaced in the event of belt failure. This tear detection system also provides a highly reliable early image of belt failure that can facilitate rapid repair before extensive belt damage occurs. More specifically, patent US 8 069 975 discloses a conveyor belt comprising (1) an elastomeric body having a load bearing surface and a parallel surface coupled to a pulley; (2) a reinforcement layer located within the elastomer body and (3) a plurality of tear detection inserts, wherein the tear detection inserts are arranged along the longitudinal length of the conveyor belt, wherein the tear detection inserts comprise a plurality of tear detection wires that consist of magnetically permeable material, the tear detection wires aligned in the tear detection inserts at an angle of 15 ° to 75 ° ° from the position perpendicular to the longitudinal direction of the strip and wherein the tear detection wires are arranged incrementally across the width of the strip. Document US 2006/020684 A1 discloses a method for detecting defects in conveyor belt connections according to the preamble of claim 1 and a conveyor system according to the preamble of claim 9, also describes a method for monitoring the state of the magnetically permeable reinforcing cables of conveyor belts.

The output signal of each magnetic sensor is converted into binary digits containing information about the existence or non-existence of a scattered magnetic field. In other words:

The description of the status of each link can be limited to two states: YES or NO. In a preferred embodiment, three states are used (YES NEGATIVE COUNTRIES, SO MUTUAL SOUGHT, or LACK OF A DROPPED FIELD

- magnetic 6). This digital sensor output is stored and sent to a location remote from said conveyor belt.

[0015] Prior art tie detection panels generate problems that may affect the integrity of the tape or the ability to replace damaged circuits. From a production point of view, panels of detection of tears with wires running transversely to the conveyor belt are desirable. However, such tear detection panels generate undesired bending properties that can cause premature failure of the conveyor belt. In any case, including detection circuits of tears or tear detection panels in a conveyor belt complicates the manufacturing method and increases the cost of the conveyor belt. Furthermore, such tear detection circuits and tear detection panels do not monitor failures in the conveyor belt connections. Accordingly, there is a need for a reliable system for monitoring defects in conveyor belt connections. It would be even more desirable for such a system to be able to monitor conventional conveyor belts that do not contain tear detection circuits or tear detection panels. Such a system would not increase the cost of the conveyor belt per se and would not degrade the durability of the conveyor belt.

Summary of the Invention [0016] A system for detecting joint failures in steel cord reinforced conveyor belts that are not part of the invention monitors the conveyor belt for joint damage during normal conveyor belt operation and can be more easily integrated into the conveyor belt system. It can be used in conjunction with conventional conveyor belts having standard one-stage, two-stage, three-stage or multi-stage connections (4 or more steps). Accordingly, the monitoring system according to the invention does not adversely affect the durability of the conveyor belt, it does not require special sensors to be incorporated into the conveyor belt and consequently does not increase the cost of the conveyor belt system.

[0017] Such a conveyor belt monitoring system also provides a highly reliable means for detecting connection failures or connection abnormalities prior to the occurrence of a catastrophic event. More precisely, it allows for early detection of connection failure, which can facilitate quick repair before extensive connection failure occurs. The connection monitoring system according to the invention also has the advantage of being able to ignore the damage to the joints that occurred prior to repair while continuing to monitor the tape for future connection failures. Also, radio identification tags can be integrated with the tapes used in the system according to the invention to identify the connections on the tape where the damage has occurred by placing them in a nearby known environment of the connection in question. The tape monitoring system of the invention may optionally include an alarm that is activated when the threshold level defined by the user is exceeded due to a deterioration in the connection condition or a new damage to the inner cord within the connection. In some cases, it is advantageous for the system to automatically stop further movement of the conveyor belt after detecting a particular level of change in the connection.

[0018] The deterioration of the connection condition can be measured by monitoring one or more parameters related to the tape connections, including the deviation angles of approach and runoff, connection deviation angles from linearity, bias of positive polarity areas and negative polarity of connections and change of the center of mass areas of positive and negative magnetic polarity, the center of mass of each area along the length of the strip and across the width of the strip and the separation of leading edge and runoff connection. In accordance with the practice of the invention, tolerance ranges are imposed on these areas, and if these tolerances are exceeded, the relay opens and provides notification about the deterioration of the connection condition. Such notification can be provided by an audible alarm, a visual alarm, an e-mail message, a text message or a combination of them. The alarm can be carried by a switch or a relay.

[0019] More specifically, the invention discloses a method of detecting defects in conveyor belt connections having magnetically penetratable metal cords built into it, according to the appended claim 1. The method of the invention can be used to detect defects in conveyor belts having single-stage or multi-stage connections that incorporate in-line connections. not magnetically permeable metal cables. In the case of multi-stage connections, magnetic images generated by a set of negative poles and a set of positive poles are monitored to detect magnetic anomalies generated by cable defects.

[0020] The present invention further discloses a conveyor system according to the annexed claim 9. Brief description of the drawings [0021]

Fig. 1 is a schematic view of a conveyor belt system according to the invention.

Fig. 2 shows the configuration of steel cables in a conventional two-stage connection.

Fig. 3 shows the polarized ends of magnetized steel wire cables in a conventional two-stage connection in a conveyor belt.

Fig. 4 is an illustration depicting magnetic images generated by one-stage connections, two-stage connections and three-stage connections in a conveyor belt.

Fig. 5 is an illustration depicting the position of the geometric center and the center of the magnetic conveyor belt connection that are within the boundary of normal and acceptable operation (which does not trigger an alarm).

Fig. 6 is an illustration depicting the change in the rake angle of the joint measured over a period of time.

Detailed description of the invention

[0022] Conveyor belts that can be monitored in accordance with the invention have an elastomer body (framework section) with a load bearing surface on its upper side and a surface coupled to the pulley on its lower side. Such conveyor belts will also include at least one reinforcing layer located within the elastomeric body and at least one connection forming an endless loop from the belt. The connections will typically connect the different segments of the tape to each other to form an endless belt that includes a plurality of segments that are connected to each other by means of connections.

[0023] The connections will typically be arranged incrementally along the length of the conveyor belt. Connections are conventional connections that can be one-step connections, two-stage connections, three-stage connections or multi-stage connections having four or more stages. In any case, the connections comprise a first set of magnetically magnetizable metal wires originating from the first side of the connection and which extend to a different side (second side) of the connection. Links from the first page of the link have ends that are embedded in a different direction (the other side) of the connection. Such connections also comprise a second set of magnetically permeable metal cables originating from another side (of the other side) of the connection and which extend to the first side of the connection.

[0024] The elastomer body will normally comprise fabric layers or reinforcing steel wires that typically run longitudinally within the conveyor belt. Conveyor belts according to the invention may optionally also comprise conventional inductive tape fault sensor circuit circuits incorporating transducer elements. Conventional tear detection systems of this type are described in U.S. Patent No. 4,621,777, U.S. Patent No. 4,854,464, U.S. Patent No. 6,715,602 and U.S. Patent No. 8,096,975. U.S. Patent 4,621,727, U.S. Patent No. 4,854,464, U.S. Patent 6,715,602 and U.S. Patent No. 8,096,975 are incorporated herein by reference for the disclosure of conventional tear identification and detection systems that may be used in connection with the invention. However, for the system according to the invention, it may be desirable to have no detection circuits for tears and tear detection inserts. In any case, the tear detection circuits or tear detection pads are not needed in the implementation of the system according to the invention.

[0025] The conveyor system 1 of the invention as shown in Fig. 1 will normally comprise a pulley system that is adapted to receive a pulley-coupled surface 3 of the monitored conveyor belt 2, means for driving the belt along the pulley system, means for generating a magnetic field or a magnetic system 5, such as a permanent magnet or an electromagnet and a sensor system 6. In many cases, it is advantageous to integrate with the conveyor system 1 a tachometer, a proximity sensor or an encoder. Such conveyor belts can advantageously be used for transferring coal, rocks, mineral ore 7 and the like over long distances. IN

- in any case, the magnetic system 5 magnetizes the steel wires 8 within the conveyor belt 2, as shown in the case of a typical two-stage connection as shown in Fig. 2.

[0026] A standard two-stage connection is shown in Figure 2. In this two-stage connection from the first side of the connection 12 comes the first set of magnetically permeable metal cables 10 and extends to the other side of the connection 13 and has ends 14, which are incorporated in the other side of the connection 13 with a second set of magnetically permeable metal lines 11 coming from the other side of the connection 13 and extending to the first side of the connection 12 and having ends 15 that are incorporated in the first side of the connection 12. The method of the invention can also be used to monitor standard single stage connections, three-stage or multi-stage connections (4 or more stages) in conventional conveyor belts.

[0027] The magnetic system magnetizes the steel wires within the monitored conveyor belt. The magnetism of the steel cords 8 generates polarized ends 14 and 15 of the cords, as shown in Fig. 3. Magnetic images generated by the ends of conveyor belts having single-stage connections, two-stage connections and three-stage connections are shown in Fig. 4. As can be seen, single-stage connections generate one northern magnetic field 16 and one southern magnetic field 17, the two-stage connection generates two northern magnetic fields 16 and two southern magnetic fields 17, and three-stage connections generate three northern magnetic fields 16 and three southern magnetic fields 17. The damage of the strip in the connection area leads to discontinuities in the geometric configuration of magnetically permeable metal cables extending through the connection, which causes a magnetic anomaly. Such magnetic anomalies, which are generated by cable damage, are measured with the magnetic sensor system 6 and can be displayed as an image, as shown in Fig. 4. The location of the damage and connections along the length and across the width of the conveyor belt can then be accurately identified. Accordingly, the system can monitor the connection of steel strap strips during the connection, thereby facilitating early detection of internal joint change that could lead to a lateral interruption at the joint. This can be additionally facilitated by statistical analysis of the connection properties.

[0028] Connection properties that can be monitored include, but are not limited to, the angle of approach of the joint, the angle of runoff, straightness of the leading edge of the joint, straightness of the trailing edge, average separation (distance between the north magnetic field and the southern magnetic field generated by the ends of the joint), change the symmetry of the connection along the length and width of the connection and the center of the magnetic field of the connection compared to the geometrical center of the connection along its length and width. Fig. 5 is an illustration depicting the geometric center 18 and the magnetic center 19 of the connection. The movement of the magnetic center 19 relative to the geometrical center 18 of the connection over time may be evidence of a failure of the connection in this time interval.

[0029] The change in the rake angle measured over a certain time is shown in Fig. 6. The normal rake angle change without any magnetic anomalies in the first 30 and the second time 31 is shown. A period in which there was no change in the rake angle shown in FIG. time 32 occurs normally when the conveyor belt is not working.

She prepared and verified

Anna Stenzel Patent attorney